Parabens are chemicals used as a preservative in a number of cosmetics and personal care products including deodorant, shampoo, makeup, lotions and oral care products, as well as in processed food items and some pharmaceutical products.

Underarm deodorants often contain parabens and have been thought to contribute to an increased risk of high paraben levels in the body that have been linked to breast cancer. But according to Darbre’s team, even women who did not use underarm deodorant were found to have parabens present in breast tissue.

The estrogen-mimicking properties of most parabens are believed to be a factor responsible for the rising cases of breast cancer. The prevalence of the number of types of paraben toxins found in the human body, however, make it difficult for researchers to conclude which of the preservatives are most likely the causal agents, but many speculate that parabens commonly found in underarm antiperspirants and deodorants can easily move into breast tissue and may result in tumors.